Control system for tandem unconnected vehicles whereby rear vehicle controls work means of the forward vehicle



Aug- 18 1954 .1. w. CARTER CONTROL SYSTEM FOR TANDEM UNCONNECTED VEHICLES WHEREBY REAR VEHICLE CONTROLS WORK MEANS OF THE FORWARD VEHICLE Filed March 1. 1961 A TT RNEY 1S' United States Patent O CONTROL SYSTEM FOR TANDEM UNCON- NECTED VEHICLES WHEREBY REAR VE- HICLE CONTROLS WORK MEANS OF THE FORWARD VEHICLE John W. Carter, Peoria, Ill., assigner to Caterpillar Tractor Co., Peoria, Ill., a corporation of California Filed Mar. 1, 1961, Ser. No. 92,665) 4 Claims. (Cl. 37-129) This invention relates to a control device for use between separate pieces of earth moving equipment or the like where the noise of operation and interference with vision prohibits an operator from manipulating his equipment in the most efficient manner.

The invention is particularly adapted to and will be described in connection with its use on an earth moving scraper and a separate pusher tractor which assists the scraper when the demand for power is the greatest. Other applications of the invention will be apparent from an understanding of the following description.

Owners of fleets of earth moving machines commonly employ scrapers in cyclic operation allied with a pusher tractor for the loading portion of the cycle. In such functions, it is desirable for most efiicient operation, that loading of the scrape cease at the proper instant. It is the present practice to employ a load boss or dirt boss, stationed at a suitable vantage point near the area of operation, whose responsibility it is to observe the load being gathered in the scraper bowl and to signal the scraper operator when the -scraper is effectively loaded. Upon receiving the signal, the operator raises the bowl of the scraper and accelerates the implement to carry the load to the place Where it is to be discharged.

In most cases, due to the noise common to these areas of work, it is difficult for the scraper operator to detect such signals. Any delay in receiving the signal may result in poor cycling of the apparatus at a construction site resulting in increased cost from moving earth. Also, in some conditions it may be economically desirable to start the scraper on its Way Without a full load. Although it would seem desirable to load the Scrapers to capacity, poor traction conditions of the road often make it impossible for a fully loaded scraper to manipulate some grades successfully.

It is also desirable for most ef'licient operation that the scraper bowl be at the proper setting to achieve an optimum cut. If the scraper bowl is set to take a cut which is too deep the equipment is overburdened and may bog down. Whereas if the bowl is set to make a cut which is too shallow the scraper will not be working at peak efficiency. It is the present practice to have a scraper operator estimate the bowl setting which will produce the most efficient cut without overburdening the equipment. Although the bowl vsetting is often changed between cycles, it is common practice to maintain a given setting for one complete cycle unless the equipment bogs down entirely. Although it is highly desirable to be able to correct a bowl setting during a cycle, the inability of the scraper operator to observe the immediate results of his work coupled with the difiiculty in communicating with others renders this function nearly impossible.

It is, therefore, an object of the present invention to provide control means by which the function of one vehicle can be controlled from another vehicle which is driven in close proximity thereto.

Another object of this invention is to provide electromechanical means by Which the operator of a scraper assisting or pusher tractor can control the operation of the scraper and thereby increase the cycle efficiency in an earth moving operation.

Further and more specic objects of this invention will ICC be made apparent in the specification wherein reference is made to the accompanying drawings.

In the drawings:

FIG. l is a semi-schematic View of a scraper and pusher tractor in tandem arrangement illustrating the conditions obtaining during the loading portion of the cycle;

FIG. 2 is a schematic and block diagram of the electromechanical system Which enables the operator of the pusher tractor to control the bowl of the scraper.

In FIG. l of the drawings, an earth moving implement, more commonly known as a scraper, is generally indicated at 10 which comprises a tractor 11 and a scraper bowl 12. During the loading cycle of the operation, an apron 14 is elevated to permit entry of the scraped material into the bowl 12. A scraper operator thus has difficulty in observing the load condition because his` vision is obscured by the apron 14.

During the loading cycle, a pusher tractor 15 is usually allied with the scraper 10 to provide the additional traction required to suitably fill the bowl 12. The operator of pusher tractor 15 is provided with a control 16 by which he may control the position of scraper bowl 12.

Referring to FIG. 2, a spring loaded switch arm 17 electrically connected to a source of D.C. potential 1S by means'of conductor 19 completes an electrical circuit when brought into contact with terminal 20 or terminal 21. Springs 22 and spring retaining members 23 hold switch arm 17 in a position midway between terminals 20 and 21 when handle 16 is unacted upon. Thus, the normal position of switch arm 17 is that which creates an open circuit and thereby renders the system inactive. When switch arm 17 is in contact with either terminal 20 or terminal 21 power from source 18 is delivered to either of audio frequency, control signal oscillators 24 or 25, respectively, by means of conductor 26 or conductor 27. Oscillators 25 and 24 respond to the power delivered from source 18 by producing an A.C. electrical signal at a set frequency. Although audio oscillators 24 and 25 are generally similar, they are tuned to generate signals of different frequencies. By way of example, oscillator 24 is tuned to generate a signal at 3500 cycles per second Whereas oscillator 25 is tuned to generate a signal at 5000 cycles per second. When a signal is generated by either of the audio oscillators that signal is introduced to a conventional modulator 28. Modulator 28 serves to impress the control signal from the audio oscillators on a carrier signal, which is supplied to modulator 28 from a conventional radio frequency oscillator 29. The carrier signal from radio frequency oscillator 29 is essential to enable the control signal to be transmitted through the air by means of antenna 30 which receives the modulated signal from modulator 28. Antenna 30 is most advantageously of the directional variety to insure that the transmitted signal 31 is received only by the scraper for which it is intended.

Signal 31 is received by a second directional antenna 32 conveniently mounted on tractor 11. The received signal is then amplified by a conventional radio frequency amplifier 33 which in turn introduces the amplified signal to a conventional audio detector 34. Audio detector 34 serves to suppress the carrier portion of the signal while passing the control portion of the signal (that portion from either oscillator 24 or oscillator 25) to an audio amplifier 35. The signal received by audio amplilier 35 will thus have a frequency of either 3500 or 5000 cycles per second depending upon which of terminals 20 or 21 was brought into contact with switch arm 17. The output from audio amplifier 35 is introduced to one of two circuits 36 or 37. Each of circuits 36 and 37 comprises a stage of amplification 38 and a transistorized static switch 39, and each is separated from amplifier 35 by an electrical band pass filter 40. Filter 40 of circuit 36 is designed to allow the passage of signals which are at a frequency of 3500 cycles per second and suppress signals which are at a frequency other than 3500 cycles per second. Filter 40 of circuit 37 is designed to pass signals which are at a frequency of 5000 cycles per second and suppress signals which are at a frequency other than 5000 cycles per second. Thus, either switch 39 of circuit 36 or switch 39 of circuit 37 will be activated depending upon which of oscillators 24 or 25 generate the signal received by audio amplier 35.

Switch 39 of circuit 36 introduces an energizing current to a solenoid 42 upon activation. Upon being energized solenoid 42 positions a valve 43 so as to allow hydraulic fluid to pass into a cylinder 46. A piston 47 in cylinder 46 is connected by means of appropriate linkage (not shown) to a brake (not shown) which prevents lowering of bowl 12. When uid is introduced to cylinder 46 piston 47 moves in response thereto and causes the release of the brake holding bowl 12 permitting it to lower. Similarly switch 39 of circuit 37 delivers an energizing current to a solenoid 48 upon activation. Solenoid 48 controls the position of a hydraulic valve 49 which admits hydraulic fluid to a cylinder 50 when switch 39 is activated. A piston 51 in cylinder 50 responds to the admission of hydraulic fluid by positioning appropriate linkage (not shown) to cause a clutch mechanism to be engaged which serves to raise bowl 12.

Thus, it is seen when switch arm 17 contacts terminal 20 a control signal operating at 3500 cycles per second is transmitted from a pusher tractor to a scraper tractor by means of conventional radio transmission. The signal is received and demodulated and allowed to pass through the band pass iilter of circuit 36 while being suppressed by the band pass lter of circuit 37. The signal causes a switch 39 to be activated which in turn energizes a solenoid which operates a valve which causes a brake to release bowl 12 and thereby lower same. Likewise, when arm 17 is contacted to terminal 21 a contact signal of 5000 c.p.s. causes a switch 39 to be activated which in turn energizes a solenoid that positions a valve that causes a clutch mechanism to engage and raise bowl 12.

1n practice it is found that the necessity to raise the scraper bowl arises more frequently than the necessity to lower the bowl. Consequently, another useful embodiment of the present invention is one utilizing a single control signal oscillator which serves to control valve 49 which in turn allows the engagement of al clutch mechanism for raising bowl 12. An embodiment wherein more than two control signals which may be of either an audio or radio frequency are available for controlling other parts of the scraper besides just raising and lowering is also believed to be well within the specification as set out above.

What is claimed is:

1. In a radio operated remote control system the combination comprising;

an earth moving scraper having a movable bowl;

a pusher vehicle for operation with said scraper;

means on said pusher vehicle for transmitting control signals on electromagnetic waves at radio frequencies;

means on said scraper for receiving electromagnetic waves at radio frequencies and providing electrical signals in response thereto; and

lmeans responsive to electrical signals from said receiving means to move the scraper bowl.

2. In a radio operated remote control system the combination comprising;

an earth moving scraper having a bowl which is movable in a generally vertical direction;

a pusher vehicle for operation with said scraper;

means on said pusher vehicle for transmitting control signals on electromagnetic waves at radio frequencies;

means on said scraper for receiving electromagnetic waves at radio frequencies with the control signal thereon and providing electrical signals in response thereto where the signals are essentially the same frequencies as the control signals;

means responsive to electrical signals of one control frequency to raise the scraper bowl and responsive to electrical signals of another control frequency to lower the bowl.

3. In a radio operated remoted control system the cornbination comprising;

an earth moving scraper having a bowl which is movable in a generally vertical direction;

a pusher vehicle for operation with said scraper;

means on said pusher vehicle for generating a radio frequency carrier signal;

control signal means for selectively modulating the radio frequency signal with one of two control signals;

means on said scraper for receiving radio frequency signals and extracting the control signal therefrom; and

means responsive to one control signal to raise the bowl and to the other control signal to lower the bowl.

4. In a radio operated remote control system the combination comprising;

an earth moving vehicle having a movable member employed to perform an earth conditioning function;

a self-motivating pusher vehicle for assisting said earth moving vehicle by furnishing added motivating force from behind;

radio signaling means on said pusher vehicle; and

means on said earth moving vehicle responsive to said radio signaling means to position said movable member.

References Cited in the file of this patent UNITED STATES PATENTS 1,484,049 Zworykin Feb. 19, 1924 1,811,857 Melhuish June 30, 1931 1,879,678 Good Sept. 27, 1932 2,515,966 Polisena July 18, 1950 2,529,804 Harnischfeger et al Nov. 14, 195() 2,796,685 Bensinger June 25, 1957 2,852,870 Kimsey et al Sept. 23, 1958 2,919,142 Winget Dec. 29, 1959 2,973,593 Zellner et al. Mar. 7, 1961 3,007,538 Hill Nov. 7, 1961 OTHER REFERENCES Farm Implement and Machinery Review, Mar. 1, 1960, Russias Automatic Tractor, pp. 1578-1580. 

4. IN A RADIO OPERATED REMOTE CONTROL SYSTEM THE COMBINATION COMPRISING; AN EARTH MOVING VEHICLE HAVING A MOVABLE MEMBER EMPLOYED TO PERFORM AN EARTH CONDITIONING FUNCTION; A SELF-MOTIVATING PUSHER VEHICLE FOR ASSISTING SAID EARTH MOVING VEHICLE BY FURNISHING ADDED MOTIVATING FORCE FROM BEHIND; RADIO SIGNALING MEANS ON SAID PUSHER VEHICLE; AND MEANS ON SAID EARTH MOVING VEHICLE RESPONSIVE TO SAID RADIO SIGNALING MEANS TO POSITION SAID MOVABLE MEMBER. 